Having fun with science and technology.

Posted: 2008-09-09 06:27

Two new versions of libquantum have been released. The
1.1.0 development release adds support for exact diagonalization,
while the 1.0.0 stable release contains only bug fixes. Further
information can be found on the libquantum website.

Posted: 2007-09-03 07:13

libquantum 0.9.1 has been released. The new release adds
an interface for time-evolution of arbitrary Hamiltonians using a
fourth-order Runge-Kutta algorithm. The license has been changed to
GPLv3 and several bugs have been fixed. Further information can be
found on the libquantum
website.

Posted: 2007-08-22 06:32

As some of you may know, I wrote my diploma thesis on transport in
quantum thermodynamics. Related to this work, we now put up a
paper on arXiv, describing how
to incorporate the concepts of work and heat, which are well-known
from the classical world, into the quantum realm.

It turns out that if you do it properly, you get some remarkable
consequences, like a machine that both works and does not at the same
time. These strange things arise (hardly surprising) from
non-commuting observables in quantum mechanics.

Posted: 2008-06-28 12:32

Rydberg atoms are
atoms with a large principle quantum number. One possibility to create
them is to excite ground state atoms with lasers. They are very
sensitive to electric fields, so if you bring them close together they
will experience very strong interactions due to static or induced
electric dipoles.

We have now put a paper onto
the arXiv, where we investigate the properties of the strongly
interacting regime. We have found some interesting links between
Rydberg physics and concepts originally coming from condensed matter
physics.

Posted: 2007-01-03 12:56

Accessing scientific papers online is great because it spares you the
way to the library. Unfortunately, most journals make their articles
available only to paying subscribers (contrary to Open
Access). So if you want
to read an article at home or while on a conference you have a
problem. This posting shows you how to access it anyway just by
clicking on the download link in a journal. Read more

Posted: 2008-10-22 20:17

I have dropped Mathematica in favor of Maxima some
time ago in order to escape from obscure bugs remaining unfixed and
licensing troubles, and have not regretted it since. Now I just came
across Qinf, which is
a free (as in GPLv2) quantum information suite for Maxima. While the
package is still under development it already contains quite a lot
useful functions like partial traces, entropy calculation, operator
expansion. So if you use Qinf instead of another package relying on
a proprietary CAS, you can prevent your code from being trapped.

Posted: 2011-09-07 06:03

By looking at the history of quantum computing experiments, one finds
an exponential increase in the number of qubits, similar to Moore's
law for classical computers. Quantum computing power doubles about
every six years, with quantum computers for real applications arriving
in between nine and twelve years if this trend continues.

Posted: 2010-04-13 18:55

I spent some time playing around with
libquantum, the free quantum
simulation library, and created two musical compositions that
represent the inner workings of a quantum computer. So if you'd like
to know what a quantum computer sounds like, here's your chance!

Posted: 2008-10-06 18:43

The American Physical Society (APS) is one of the most important
publishers in physics, well-known for its Physical Review
journals, including their flagship Physical Review Letters. Like
most other publishers, APS requires authors to transfer copyright,
meaning you may not use the materials elsewhere without permission
from the APS. This created trouble for some researchers who
wanted to put their research on Wikipedia and other open content
sites because the
APS refused to permit them to do so. Fortunately, the APS has now
changed their
copyright policy, thus resolving the issue.

Posted: 2008-06-06 06:43

A
paper
(also available
here)
published yesterday in Nature analyzes moving patterns of humans based
on position data provided by a European mobile network operator. While
the paper itself is very interesting and provides new insights it also
raises serious privacy concerns, and maybe even legal troubles for the
telco in question.